Some known vehicle systems include multiple vehicles connected together so that the vehicles can travel together. Such vehicle systems can be referred to as consists. Some rail vehicle systems can include multiple consists that each includes locomotives (or other powered rail vehicles) providing propulsive force.
The operations of the locomotives can be coordinated with each other by remotely controlling some locomotives from another locomotive in the rail vehicle. For example, distributed power (DP) control of the locomotives may involve all locomotives in the rail vehicle system (e.g., a train) being controlled to have the same throttle and/or brake settings at the same time. Alternatively, the locomotives in a first consist of the rail vehicle system may operate with the same throttle or brake settings while the locomotives in a different, second consist of the same rail vehicle system operate with throttle or brake settings that are the same, but different from the settings used by the locomotives in the first consist. In the terminology of current distributed power systems, it is said that the fence is set up between the first and second consist.
Because rail vehicle systems may be very long, different segments of the rail vehicle systems may experience different grades and/or curvatures in a track at the same time. Using the same throttle or brake settings for multiple locomotives traveling over different grades and/or curvatures can result in undesirable forces on couplers of the rail cars that are located between the locomotives and/or undesirable movements of the rail cars. For example, when cresting a hill, using the same throttle settings on all locomotives can cause the rail cars located at or near the apex of the hill to experience relatively large tensile forces, can cause the rail cars on the downward slope of the hill to move faster than and away from other rail cars at or near the apex, and/or can cause the rail cars on the upward slope of the hill to move slower than and away from the other rail cars at or near the apex. These forces and/or movements can damage the couplers, cause the rail vehicle system to break apart, and/or generally degrade handling of the rail vehicle system as experienced by an operator of the rail vehicle system.
Some known vehicle systems do not individually control brakes of different vehicles. For example, a train may include several locomotives with rail cars having electronically controlled pneumatic (ECP) brakes. During movement, the vehicle system does not separately control the brakes of different rail cars in different ways. Instead, all rail cars may apply the brakes at the same time. Due to the length of some vehicle systems, different portions of the same vehicle system may experience different grades and/or curvatures at the same time. Consequently, applying the brakes for some vehicles may be inappropriate but needed for other vehicles at the same time.